Design hazard analysis, and system level testing of a university propulsion system for spacecraft application

The Missouri Science and Technology Satellite (M-SAT) design team on the campus of the Missouri University of Science and Technology has developed a pair of satellites to perform an autonomous formation flight mission. To enable the mission, a unique cold gas propulsion system was developed which utilizes the refrigerant R-134a as propellant. This thesis details the design process and considerations which led to the propulsion system as integrated into the satellite for the Flight Competition Review of the NS4 competition. The design process described flowed from the mission requirements and program restrictions down through component-level requirements and resulted in a system capable of performing the assigned duties. The hazard analysis conducted for this thesis also expanded on previous analyses to address key issues and AFRL concerns --Abstract, page iii

Preimplantation genetic screening during in vitro fertilization, clinical applications and insight into embryological development

Aneuploidy (extra or missing individual chromosomes) is the leading cause of miscarriage, embryo wastage and in-vitro fertilization (IVF) failure. Aneuploidy increases with maternal age and is widespread in human preimplantation embryos. Thus, aneuploidy screening before implantation during an IVF cycle (preimplantation genetic screening or PGS), to increase pregnancy rates and decreasing miscarriage rates, is also widespread. Despite this, PGS faces challenges in terms of both biological and technical limitations that may impede its full potential. Biologically, the phenomenon of chromosomal mosaicism (the presence of two or more cell lines - typically, one aneuploid and one euploid) may lead to false positives or false negatives, and the discard or transfer of euploid or aneuploid embryos, respectively. Technically, it is uncertain whether diagnosis on the biopsied piece is representative of the remaining embryo. Because these dilemmas it is unknown if PGS will only benefit a few selected groups of patients or potentially the entire IVF patient population. In a series of published works, this thesis demonstrates a significant contribution to field of preimplantation genetics, provides insight into technical and biological limitations of PGS, and into the etiology of aneuploidy and mosaicism. Specifically, I introduce a novel technique to "map" chromosomal mosaicism, by reconstructing a virtual image of the blastocyst with the approximate location of individual cells and their corresponding chromosomal makeup. I also demonstrate the ability of PGS to be performed on blastocysts that were previously frozen; thus, blastocysts have to be thawed/warmed, biopsied, vitrified and rewarmed prior to use. From a clinical standpoint, I present evidence of the differences in PGS outcomes between day 5 and day 6 blastocysts: The data suggests that day 6 blastocysts are less likely to be euploid than day 5 blastocysts. Furthermore, day 6 euploid blastocysts exhibit similar pregnancy and implantation rates when compared to their day 5 counterparts. I also published on a study examining differences in PGS outcomes in those patients that are defined as "presumed fertile" as opposed to those that are "infertile". Another study examined pregnancy and implantation rates between two competing platforms, quantitative polymerase chain reaction (qPCR) and array comparative genomic hybridization (aCGH). I also examined the pregnancy rates of poor quality embryos on day 6 that would have been discarded. From a biological standpoint, I examined the mechanisms through which embryos diagnosed as aneuploid on day 3 could develop to a euploid blastocyst, demonstrating that euploid blastocysts can develop from aneuploid cleavage stage embryos. I also demonstrated differences in aneuploidy rates between polar, mural, and a piece defined as "mid" trophectoderm, and blastocysts diagnosed as aneuploid may not reflect the chromosomal constitution of the whole embryo proper. This work herein presented provides a deeper understanding of the technical limitations of PGS and into the etiology of the chromosomal basis of early human development

Securing Virtualized System via Active Protection

Virtualization is the predominant enabling technology of current cloud infrastructure

1st EFORT European Consensus: Medical & Scientific Research Requirements for the Clinical Introduction of Artificial Joint Arthroplasty Devices

Innovations in Orthopaedics and Traumatology have contributed to the achievement of a high-quality level of care in musculoskeletal disorders and injuries over the past decades. The applications of new implants as well as diagnostic and therapeutic techniques in addition to implementation of clinical research, have significantly improved patient outcomes, reduced complication rates and length of hospital stay in many areas. However, the regulatory framework is extensive, and there is a lack of understanding and clarity in daily practice what the meaning of clinical & pre‐clinical evidence as required by the MDR is. Thus, understanding and clarity are of utmost importance for introduction of new implants and implant-related instrumentation in combination with surgical technique to ensure a safe use of implants and treatment of patients. Therefore EFORT launched IPSI, The Implant and Patient Safety Initiative, which starting from an inaugural workshop in 2021 issued a set of recommendations, notably through a subsequent Delphi Process involving the National Member Societies of EFORT, European Specialty Societies as well as International Experts. These recommendations provide surgeons, researchers, implant manufacturers as well as patients and health authorities with a consensus of the development, implementation, and dissemination of innovation in the field of arthroplasty. The intended key outcomes of this 1st EFORT European Consensus on “Medical & Scientific Research Requirements for the Clinical Introduction of Artificial Joint Arthroplasty Devices”are consented, practical pathways to maintain innovation and optimisation of orthopaedic products and workflows within the boundaries of MDR 2017/745. Open Access practical guidelines based on adequate, state of the art pre-clinical and clinical evaluation methodologies for the introduction of joint replacements and implant-related instrumentation shall provide hands-on orientation for orthopaedic surgeons, research institutes and laboratories, orthopaedic device manufacturers, Notified Bodies but also for National Institutes and authorities, patient representatives and further stakeholders. We would like to acknowledge and thank the Scientific Committee members, all International Expert Delegates, the Delegates from European National & Specialty Societies and the Editorial Team for their outstanding contributions and support during this EFORT European Consensus

Report to users of ATLAS, January 1998

This report is aimed at informing users about the operating schedule, user policies, and recent changes in research capabilities. It covers the following subjects: (1) status of the Argonne Tandem-Linac Accelerator System (ATLAS) accelerator; (2) the move of Gammasphere from LBNL to ANL; (3) commissioning of the CPT mass spectrometer at ATLAS; (4) highlights of recent research at ATLAS; (5) Program Advisory Committee; and (6) ATLAS User Group Executive Committee

Multifaceted evaluation of a binaural cochlear‐ implant sound‐processing strategy inspired by the medial olivocochlear reflex

[ES]El objetivo de esta tesis es evaluar experimentalmente la audición de los usuarios de implantes cocleares con una estrategia de procesamiento binaural de sonidos inspirada en el reflejo olivococlear medial, denominada "estrategia MOC". La tesis describe cuatro estudios dirigidos a comparar la inteligibilidad del habla en ruido, la localización de fuentes sonoras y el esfuerzo auditivo con procesadores de sonido estándar y con diversos procesadores MOC diseñados para reflejar de forma más o menos realista el tiempo de activación del reflejo olivococlear medial natural y sus efectos sobre la comprensión coclear humana

The development of an adaptive and reactive interface system for lower limb prosthetic application

Deep tissue injury (DTI) is a known problem correlating to the use of a prosthetic by a transtibial amputee (TTA), causing ulcer-like wounds on the residual limb caused by stress-induced cell necrosis. The magnitude of these stresses at the bone tissue interface has been identified computationally, far exceeding those measured at the skin's surface. Limited technology is available to directly target and reduce such cellular loading and actively reduce the risk of DTI from below-knee use. The primary aim of this project was to identify whether a bespoke prosthetic socket system could actively stiffen the tissues of the lower limb. Stabilising the residual tibia during ambulation and reducing stress concentrations on the cells. To achieve this, a proof-of-concept device was designed and manufactured, a system that allowed the change in displacement of a magnet to be responded to by counterbalancing load. The device was evaluated through experimentation on an able-bodied subject wearing an orthotic device designed to replicate the environment of a prosthetic socket. The chosen sensor effector system was validated against vector data generated by the Motek Medical Computer Assisted Rehabilitation Environment (CAREN.) The project explored a new concept of reactive loading of a below-knee prosthesis to reduce tibial/socket oscillation. The evaluation of the device indicated that external loading of the residual limb in such a manner could reduce the magnitude of rotation about the tibia and therefore minimise the conditions by which DTIs are known to occur. Efforts were made to move the design to the next iteration, focusing on implementing the target demographic.Deep tissue injury (DTI) is a known problem correlating to the use of a prosthetic by a transtibial amputee (TTA), causing ulcer-like wounds on the residual limb caused by stress-induced cell necrosis. The magnitude of these stresses at the bone tissue interface has been identified computationally, far exceeding those measured at the skin's surface. Limited technology is available to directly target and reduce such cellular loading and actively reduce the risk of DTI from below-knee use. The primary aim of this project was to identify whether a bespoke prosthetic socket system could actively stiffen the tissues of the lower limb. Stabilising the residual tibia during ambulation and reducing stress concentrations on the cells. To achieve this, a proof-of-concept device was designed and manufactured, a system that allowed the change in displacement of a magnet to be responded to by counterbalancing load. The device was evaluated through experimentation on an able-bodied subject wearing an orthotic device designed to replicate the environment of a prosthetic socket. The chosen sensor effector system was validated against vector data generated by the Motek Medical Computer Assisted Rehabilitation Environment (CAREN.) The project explored a new concept of reactive loading of a below-knee prosthesis to reduce tibial/socket oscillation. The evaluation of the device indicated that external loading of the residual limb in such a manner could reduce the magnitude of rotation about the tibia and therefore minimise the conditions by which DTIs are known to occur. Efforts were made to move the design to the next iteration, focusing on implementing the target demographic

Furnace System Improvements

This Final Design Review (FDR) documents the work done by the group to manufacture the system to deliver improvements to the furnace in the Cal Poly microfabrication laboratory (better known as the cleanroom). The document describes the material covered in the Scope of Work (SOW), including background research, customer needfinding, and the problem statement, material associated with concept development and selection for Preliminary Design Review (PDR), material detailing the design and manufacturing plan of the system for Critical Design Review (CDR), and new material detailing the manufacture of the system for FDR. Research done for the SOW resulted in a list of engineering and customer specifications. These in turn led to the development of the goal of the project: to make the furnace system more user- friendly to operate by simplifying the tubing layout, introducing digital control, and creating a consolidated user interface. Following the development of the problem statement, the problem was decomposed into its individual functions, and solutions developed for each function. These solutions were analyzed, and the best were combined into a final design. The solution is a system consisting of a tubing subsystem, a user interface, and a control subsystem to connect the two. A prototype system has been designed to test key functionalities of the control system, and design, manufacturing, and test plans have been created for the subsystems. The system was intended to allow the user to set up a temperature and gas program, start the run, and not interact further with the system until the end of the run. In the event of an unsafe condition detection, the system would raise an alert (it was assumed that users would remain in the room as a matter of safety during runs). The fluid lines were vastly simplified, and gas programming is performed on a touchscreen user interface connected to a Raspberry Pi board. It was originally intended to be able to perform temperature programming on the same interface, but this functionality has been removed from the project as a matter of safety, as requested by the sponsors. The new interface and all controlling functions run on software written by the team, which is publicly available and free for any subsequent project to modify and use. The openness of this setup allows further improvements to the electronics and software as necessary. The system was mostly built as designed, although several key functionalities are incomplete. As such, the system was not installed in the cleanroom. Therefore, finishing the remaining components and installing them in the cleanroom are tasks which are left to subsequent senior project teams. Next steps for subsequent projects include implementing bubbler refill, building a graphical user interface for the gas routing system, implementing communication with the thermocouples, installing the pressure monitoring system, and implementing automatic gas switching. After this, the system may be installed. Upon installation, the original gas programming interface will be retained, and the new system will be installed so that it will be possible to throw a switch to revert to the old interface in the event of system malfunction

High Fidelity Bioelectric Modelling of the Implanted Cochlea

Cochlear implants are medical devices that can restore sound perception in individuals with sensorineural hearing loss (SHL). Since their inception, improvements in performance have largely been driven by advances in signal processing, but progress has plateaued for almost a decade. This suggests that there is a bottleneck at the electrode-tissue interface, which is responsible for enacting the biophysical changes that govern neuronal recruitment. Understanding this interface is difficult because the cochlea is small, intricate, and difficult to access. As such, researchers have turned to modelling techniques to provide new insights. The state-of-the-art involves calculating the electric field using a volume conduction model of the implanted cochlea and coupling it with a neural excitation model to predict the response. However, many models are unable to predict patient outcomes consistently. This thesis aims to improve the reliability of these models by creating high fidelity reconstructions of the inner ear and critically assessing the validity of the underlying and hitherto untested assumptions. Regarding boundary conditions, the evidence suggests that the unmodelled monopolar return path should be accounted for, perhaps by applying a voltage offset at a boundary surface. Regarding vasculature, the models show that large modiolar vessels like the vein of the scala tympani have a strong local effect near the stimulating electrode. Finally, it appears that the oft-cited quasi-static assumption is not valid due to the high permittivity of neural tissue. It is hoped that the study improves the trustworthiness of all bioelectric models of the cochlea, either by validating the claims of existing models, or by prompting improvements in future work. Developing our understanding of the underlying physics will pave the way for advancing future electrode array designs as well as patient-specific simulations, ultimately improving the quality of life for those with SHL

Summary of flat-plate solar array project documentation. Abstracts of published documents, 1975 to June 1982

Technologies that will enable the private sector to manufacture and widely use photovoltaic systems for the generation of electricity in residential, commercial, industrial, and government applications at a cost per watt that is competitive with other means is investigated. Silicon refinement processes, advanced silicon sheet growth techniques, solar cell development, encapsulation, automated fabrication process technology, advanced module/array design, and module/array test and evaluation techniques are developed